package com.example.demo.filter;

import com.example.demo.shiro.JWTToken;
import com.example.demo.util.JWTUtil;
import lombok.extern.slf4j.Slf4j;
import org.apache.shiro.web.filter.authc.BasicHttpAuthenticationFilter;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * @author Eric Wu
 * @since 1.8
 * create 2020-06-09
 */
@Slf4j
@Component
public class JWTFilter extends BasicHttpAuthenticationFilter {

    @Autowired
    private JWTUtil jwtUtil;

    @Override
    protected boolean isLoginAttempt(ServletRequest request,
                                     ServletResponse response) {
        HttpServletRequest req = (HttpServletRequest) request;
        String authorization = req.getHeader("Authorization");
        return StringUtils.hasText(authorization);
    }

    @Override
    protected boolean executeLogin(ServletRequest request,
                                   ServletResponse response) throws Exception {
        HttpServletRequest req = (HttpServletRequest) request;
        String authorization = req.getHeader("Authorization");
        JWTToken jwtToken = new JWTToken(authorization);
        getSubject(request,response).login(jwtToken);
        return true;
    }

    @Override
    protected boolean isAccessAllowed(ServletRequest request,
                                      ServletResponse response,
                                      Object mappedValue) {
        if(isLoginAttempt(request,response)){
            try {
                executeLogin(request,response);
            }catch (Exception e){
                response401(request,response);
            }
        }
        return true;
    }

    private void response401(ServletRequest request,ServletResponse res){
        try{
            HttpServletResponse httpServletResponse =(HttpServletResponse) res;
            httpServletResponse.sendRedirect("/401");
        }catch (IOException e){
            log.error(e.getMessage());
        }
    }

    @Override
    protected boolean preHandle(ServletRequest request,
                                ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        httpServletResponse.setHeader("Access-control-Allow-Origin", httpServletRequest.getHeader("Origin"));
        httpServletResponse.setHeader("Access-Control-Allow-Methods", "GET,POST,OPTIONS,PUT,DELETE");
        httpServletResponse.setHeader("Access-Control-Allow-Headers", httpServletRequest.getHeader("Access-Control-Request-Headers"));
        // 跨域时会首先发送一个option请求，这里我们给option请求直接返回正常状态
        if (httpServletRequest.getMethod().equals(RequestMethod.OPTIONS.name())) {
            httpServletResponse.setStatus(HttpStatus.OK.value());
            return false;
        }
        return super.preHandle(request, response);
    }
}
